Photovoltaic roofing elements and photovoltaic roofing systems

ABSTRACT

The present invention relates generally to the photovoltaic generation of electrical energy. The present invention relates more particularly to photovoltaic arrays for use in photovoltaically generating electrical energy. Aspects of the present invention provide a variety of photovoltaic roofing elements and systems that include, for example, interlocking geometries to provide for water handling and integration with conventional roofing materials; and wire management features that can protect wiring and associated electrical components from physical and/or environmental damage.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 14/993,901, U.S. Pat. No. 9,755,573, which is a continuation ofU.S. patent application Ser. No. 14/715,278, U.S. Pat. No. 9,270,224;which is a continuation of U.S. patent application Ser. No. 14/159,278,U.S. Pat. No. 9,032,672, which is a continuation of U.S. patentapplication Ser. No. 13/326,094, U.S. Pat. No. 8,631,614, which claimspriority to U.S. Provisional Patent Application Ser. No. 61/429,053;U.S. Provisional Patent Application Ser. No. 61/528,631; and U.S.Provisional Patent Application Ser. No. 61/559,614, each of which ishereby incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates generally to the photovoltaic generationof electrical energy. The present invention relates more particularly tophotovoltaic roofing products for use in photovoltaically generatingelectrical energy.

2. Technical Background

The search for alternative sources of energy has been motivated by atleast two factors. First, fossil fuels have become increasinglyexpensive due to increasing scarcity and unrest in areas rich inpetroleum deposits. Second, there exists overwhelming concern about theeffects of the combustion of fossil fuels on the environment due tofactors such as air pollution (from NO_(x), hydrocarbons and ozone) andglobal warming (from CO₂). In recent years, research and developmentattention has focused on harvesting energy from natural environmentalsources such as wind, flowing water, and the sun. Of the three, the sunappears to be the most widely useful energy source across thecontinental United States; most locales get enough sunshine to makesolar energy feasible.

Accordingly, there are now available components that convert lightenergy into electrical energy. Such “photovoltaic cells” are often madefrom semiconductor-type materials such as doped silicon in either singlecrystalline, polycrystalline, or amorphous form. The use of photovoltaiccells on roofs is becoming increasingly common, especially as systemperformance has improved. They can be used, for example, to provide atleast a significant fraction of the electrical energy needed for abuilding's overall function; or they can be used to power one or moreparticular devices, such as exterior lighting systems and well pumps.

Accordingly, research and development attention has turned toward thedevelopment of photovoltaic products that are adapted to be installed ona roof. While stand-alone photovoltaic modules have been in use for sometime, they tend to be heavy and bulky, and aesthetically unfavorablewhen installed on a roof. Roofing products having photovoltaic cellsintegrated with roofing products such as shingles, shakes or tiles, orroofing panels have been proposed. Examples of such proposals have beendisclosed in U.S. Patent Application Publications nos. 2006/0042683A1,2008/0149163A1, 2010/0313499A1 and 2010/0313501A1, and in U.S. Pat. No.4,040,867, each of which is hereby incorporated by reference herein inits entirety. A plurality of such photovoltaic roofing elements (i.e.,including photovoltaic media integrated with a roofing product) can beinstalled together on a roof, and electrically interconnected to form aphotovoltaic roofing system that provides both environmental protectionand photovoltaic power generation. These can be very advantageous, butcan be difficult to install on steep surfaces, while ensuring sufficientclosure of the roof against the elements, particularly wind driven rain,and can often result in incomplete coverage of the roof surface withphotovoltaic power generation. Moreover, as it is often desirable tohave photovoltaic roofing elements covering a portion of a roof surfaceand conventional roofing products covering the remainder of the surface,there is a need for systems that provide aesthetic effect in thetransition zone between the conventional roofing products and thephotovoltaic roofing elements while closing the roof and the array ofphotovoltaic roofing elements to the environment.

Individual photovoltaic roofing elements within a larger photovoltaicroofing system are often electrically interconnected using wiring suchas wires or cables. Similarly, wiring is often used to connect the arrayto an electrical system. But in many systems, the wiring is at risk ofbeing dislocated, being damaged, or being pinched or bent into a radiustighter than allowed by code during handling and installation. This riskis especially high when the photovoltaic roofing element includessupport structures such as downward-facing ribs, as the installer maynot be able to determine if wiring is pinched between the supportstructure and the underlying roof deck. Damaged wire can cause powerloss over time, injury, or fire, and is therefore undesirable.

There remains a need for photovoltaic products that address one or moreof these deficiencies.

SUMMARY OF THE INVENTION

One aspect of the invention is a frame structure having an upward-facingsurface and a downward-facing surface, the frame structure having anattachment zone and an exposure zone, with the exposure zone disposedtoward the bottom end of the frame structure, and the attachment zonedisposed toward the top end of the frame structure; and one or morephotovoltaic elements held in the exposure zone of the frame structure.

Another aspect of the invention is a frame structure having anupward-facing surface and a downward-facing surface, the frame structurehaving an attachment zone and an exposure zone, with the exposure zonedisposed toward the bottom end of the frame structure, and theattachment zone disposed toward the top end of the frame structure, theframe structure further including a wiring containment structure; andone or more photovoltaic elements held in the exposure zone of the framestructure.

Another aspect of the invention is a frame structure having anupward-facing surface and a downward-facing surface, the frame structurehaving an attachment zone and an exposure zone, with the exposure zonedisposed toward the bottom end of the frame structure, and theattachment zone disposed toward the top end of the frame structure, theframe structure further including includes sidelap portions disposed atits lateral edges and having geometries adapted to interlock withadjacent photovoltaic roofing elements to provide water drainagechannels; and one or more photovoltaic elements held in the exposurezone of the frame structure.

Another aspect of the invention is a photovoltaic roofing systemdisposed on a roof deck having an top end and a bottom end, thephotovoltaic roofing system comprising: one or more photovoltaic roofingelements as described herein; a plurality of roofing elements disposedadjacent the contiguously-disposed photovoltaic roofing elements, alongtheir side edges; and side flashing elements disposed along the sideedges of the contiguously-disposed photovoltaic roofing elements, theside flashing elements having a cross-sectional shape comprising avertically-extending feature and a flange extending away from a lateralside at the downward end of the vertically-extending feature, with theflange facing away from the contiguously-disposed photovoltaic roofingelements and being at least partially disposed between a roofing elementand the roof deck, the vertically-extending feature including a matchedinterlocking geometry adapted to interlock with the sidelap portion ofan adjacent photovoltaic roofing element.

Another aspect of the invention is a method for installing aphotovoltaic roofing system on a roof deck having a top end and a bottomend, the roof deck having disposed thereon a plurality of roofingelements method including continguously disposing one or morephotovoltaic roofing elements on the roof deck, each photovoltaicroofing element comprising a frame structure having an upward-facingsurface and a downward-facing surface having a top end and a bottom end,the frame structure having an attachment zone and an exposure zone, withthe exposure zone disposed toward the bottom end of the frame structure,and the attachment zone disposed toward the top end of the framestructure; and one or more photovoltaic elements held in the exposurezone of the frame structure, the contiguously-disposed photovoltaicelements together having a top edge facing the top end of the roof deck,a bottom edge facing the bottom end of the roof deck, and two side edgeswherein the roofing elements are disposed along the side edges, thesidelap portions of the photovoltaic roofing elements interlocking toprovide water drainage channels; and disposing side flashing elementsdisposed along the side edges of the contiguously-disposed photovoltaicroofing elements, the side flashing elements having a cross-sectionalshape comprising a vertically-extending feature and a flange extendingaway from a lateral side at the downward end of the vertically-extendingfeature, with the flange facing away from the contiguously-disposedphotovoltaic roofing elements and being at least partially disposedbetween a roofing element and the roof deck, the vertically-extendingfeature including a matched interlocking geometry adapted to interlockwith the sidelap portion of an adjacent photovoltaic roofing element.

The invention will be further described with reference to embodimentsdepicted in the appended figures. It will be appreciated that elementsin the figures are illustrated for simplicity and clarity and have notnecessarily been drawn to scale. For example, the dimensions of some ofthe elements in the figures may be exaggerated relative to otherelements to help to improve understanding of embodiments of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are not necessarily to scale, and sizes ofvarious elements can be distorted for clarity.

FIG. 1 is a schematic plan view of a photovoltaic roofing elementincluding a frame structure according to one embodiment of theinvention;

FIG. 1A is a partial schematic perspective view of a frame structureaccording to one embodiment of the invention;

FIGS. 2 and 3 are partial schematic cross-sectional views of a framestructure according to one embodiment of the invention;

FIG. 4 is a schematic plan view of a photovoltaic roofing elementincluding a frame structure according to one embodiment of theinvention;

FIG. 5 is a schematic cross-sectional view of a frame structureaccording to one embodiment of the invention;

FIG. 6 is a schematic plan view of a frame structure according to oneembodiment of the invention;

FIG. 7 is a schematic plan view of a photovoltaic roofing elementaccording to one embodiment of the invention;

FIG. 8 is a partial schematic cross-sectional view of two courses ofphotovoltaic roofing elements according to one embodiment of theinvention;

FIG. 9 is a pair of schematic views of a wind clip suitable for use withcertain embodiments of the invention;

FIGS. 10A and 10B are partial cross-sectional partial schematic views ofthe installation of a photovoltaic element in a frame structureaccording to one embodiment of the invention, and FIG. 10C is a partialcross-sectional schematic view of a comparative example;

FIG. 11 is a perspective schematic view of a frame structure suitablefor use in certain embodiments of the invention;

FIG. 12 is a cross-sectional partial schematic view of a photovoltaicroofing element according to one embodiment of the invention;

FIG. 13 is perspective schematic view of a frame structure suitable foruse in certain embodiments of the invention;

FIG. 14 is a cross-sectional schematic view of a photovoltaic roofingelement according to one embodiment of the invention;

FIG. 15 is perspective schematic view of a frame structure suitable foruse in certain embodiments of the invention;

FIG. 16 is a perspective/cross-sectional schematic view of a framestructure suitable for use in certain embodiments of the invention;

FIGS. 17A and 17B are partial cross-sectional partial schematic views ofthe installation of a photovoltaic element in a frame structureaccording to one embodiment of the invention;

FIGS. 18A, 18B and 18C are edge partial schematic views of photovoltaicroofing elements according to certain embodiments of the invention;

FIG. 19 is a cross-sectional schematic view of a frame structureconstructed from two pieces according to one embodiment of theinvention;

FIGS. 20-23 are various views of an example of a photovoltaic roofingelement according to one embodiment of the invention;

FIGS. 24A and 24B top are and bottom perspective schematic views,respectively, of a starter strip for use an array of photovoltaicroofing elements according to certain embodiments of the invention;

FIG. 25 is a schematic perspective view of a small array of thephotovoltaic roofing elements of FIG. 22;

FIG. 26 is a partial schematic perspective view of a photovoltaicroofing system according to one embodiment of the invention;

FIGS. 27-29 are schematic top and edge views of top flashing piecessuitable for use in certain embodiments of the invention;

FIG. 30 is a set of schematic views of side flashing pieces suitable foruse in certain embodiments of the invention;

FIG. 31 is a set of schematic views of opposing side flashing piecessuitable for use in certain embodiments of the invention;

FIG. 32 is a set of schematic views of cant strips suitable for use incertain embodiments of the invention;

FIG. 33 is a pair of partial schematic perspective views of aphotovoltaic roofing system according to one embodiment of theinvention;

FIGS. 34 and 35 are schematic plan views of photovoltaic roofing systemsaccording to certain embodiment of the invention;

FIG. 36 is a schematic cross-sectional view of interlocking photovoltaicroofing elements according to one embodiment of the invention;

FIG. 37 is a schematic perspective view of a stepped side flashing pieceaccording to one embodiment of the invention

FIG. 38 is a schematic plan view of angled side inserts suitable for usein certain embodiments of the invention;

FIG. 39 is a pair of partial schematic views of a photovoltaic roofingelement according to one embodiment of the invention;

FIGS. 40-42 are schematic cross-sectional views of ridge structuressuitable for use in certain embodiments of the invention;

FIGS. 43 and 44 are partial schematic views of photovoltaic roofingelements according to certain embodiments of the invention;

FIGS. 45-47 are schematic cross-sectional views of photovoltaic roofingelements according to certain embodiments of the invention;

FIGS. 48 and 49 are partial schematic cross-sectional views of framestructures according to certain embodiments of the invention;

FIG. 50 is a cross-sectional plan view of photovoltaic roofing elementsaccording to one embodiment of the invention disposed in an array;

FIGS. 51A-51J form a set of partial cross-sectional views of framestructures according to a variety of embodiments of the invention;

FIG. 52 is a pair of partial schematic views of a frame structureaccording to one embodiment of the invention;

FIG. 53 is a partial cross-sectional view of a frame structure accordingto one embodiment of the invention; and

FIG. 54 is a partial plan view of a photovoltaic roofing elementaccording to one embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

One aspect of the invention is a photovoltaic roofing element,configured to be disposed on a roof deck having a top end (i.e., towardthe ridge of the roof) and a bottom end (i.e., toward the eave of theroof). The photovoltaic roofing element includes a frame structurehaving an upward-facing surface and a downward-facing surface. The framestructure includes an attachment zone and an exposure zone, with theexposure zone disposed toward the bottom end of the frame structure, andthe attachment zone disposed toward the top end of the frame structure.The photovoltaic roofing element further includes one or morephotovoltaic elements held in the frame structure.

In certain embodiments, the frame structure includes sidelap portionsdisposed at its lateral edges and having geometries adapted to interlockwith adjacent photovoltaic roofing elements to provide water drainagechannels. For example, in one embodiment, the sidelap portion at onelateral edge has an upward-facing water drainage channel; and thesidelap portion at the other lateral edge has a downward-facing flangethat fits into the water drainage channel of an adjacent (e.g.,identical) photovoltaic roofing element. This configuration ispreferred, as it allows a single type of photovoltaic roofing element tobe used in an installation. Of course in other embodiments, a singlephotovoltaic element can have two upward-facing water drainage channels,or two downward-facing flanges in its sidelap portions; as long as suchphotovoltaic roofing elements are properly mated with the correspondingfeatures on adjacent photovoltaic roofing elements, they can be used toconstruct a water-tight photovoltaic roofing system.

When installed, any water that moves over the lateral edges of thephotovoltaic roofing element will be delivered into the water drainagechannel, where it can be delivered down the roof. In certainembodiments, the water drainage channel is open at the bottom edge ofthe frame structure, such that water can flow out of it and down overthe next course of photovoltaic roofing elements.

In certain embodiments, the frame structure includes sidewalls that atleast partially define the area in which the one or more photovoltaicelements are held. The sidewalls desirably form a substantially closedpolygon, e.g., a rectangle formed by sidewalls on all four sides. Thesidewalls, e.g., those on the top sidewall and/or the bottom sidewall,can include drainage channels (formed for example as smalldiscontinuities in the sidewalls) to allow water to drain down the roof.In certain embodiments, the sidewalls substantially enclose the area inwhich the one or more photovoltaic elements are held; and the one ormore photovoltaic elements substantially fill the area defined by thesidewalls. For example, the one or more photovoltaic elements and/or atransparent cover element covering the photovoltaic elements desirablyfit within 3 mm, within 2 mm, or even within 1 mm of the sidewalls. Thesidewalls are desirably in the range of 2 mm-1 cm in height. In certainembodiments, one or more of the sidewalls do not extend beyond theheight of the photovoltaic elements (i.e., in the plane of the one ormore photovoltaic elements).

One embodiment of the invention is shown in top view and in variouspartial cross-sectional views in FIG. 1. The photovoltaic roofingelement 100 of FIG. 1 includes a frame structure 110 having anupward-facing surface and a downward-facing surface. When thephotovoltaic roofing element is installed on a roof, the downward-facingsurface generally faces the roof surface, while the upward-facingsurface generally toward the sky.

More specifically, in certain embodiments, and in the embodiment of FIG.1, the frame structure has a sidelap feature 113 at its left side, and ashiplap feature 114 at its right side, equipped with water dams anddrainage paths to minimize water intrusion into the roof. The shiplapfeature 114 includes a water drainage channel; and sidelap feature 113includes a downward-facing flange that is configured to fit in the waterdrainage channel of the shiplap feature of an adjacent photovoltaicroofing element. As will be described in more detail hereinbelow, suchphotovoltaic roofing elements can be installed on a roof using flashinghaving coordinating dam and drainage structures. Photovoltaic roofingelements of this type are described in more detail in U.S. ProvisionalPatent Application Nos. 61/429,053 and 61/528,631, each of which ishereby incorporated herein by reference in its entirety.

In the embodiment of FIG. 1, the exposure area 116 of the framestructure is equipped with two rows of seven photovoltaic elements 170,each about 5″×5″ in dimension. For the sake of clarity, and in order toshow the details of the frame structure, only two such photovoltaicelements are shown. The frame structure has a top edge 120, a bottomedge 121, a right edge 122 and a left edge 124. When installed on a roofdeck, the top edge is disposed toward the ridge side of the roof deck(i.e., toward its top end), and the bottom edge is disposed toward theeave side of the roof deck (i.e. toward its bottom end). In theembodiment of FIG. 1, near the top end is an attachment zone 126 forfastening the photovoltaic roofing element to a roof structure. A raisedlip 128 is provided at the top end of the attachment zone as a damagainst water, in order to help prevent moisture intrusion over theupper edge of the photovoltaic roofing element and help to close theroof to the environment. Mounting tabs 129 are provided at severallocations across the width of the attachment zone with raised nailbosses, the raised structure providing additional protection from waterintrusion through the nail holes. Near the bottom end of the attachmentzone is a top sidewall 130, delineating the top edge of the area inwhich the one or more photovoltaic elements are disposed. Spaced alongthis top sidewall are drainage openings (e.g., slots or weep holes) 131,such that any water in the attachment zone can drain down the roof overthe exposure area 116 of the photovoltaic roofing element.

A top perspective view of a similar frame structure is shown in FIG. 1A.The frame structure of FIG. 1A includes top sidewall 130, as well assidewalls 132 and 134, defining the left, and bottom edges of the areain which the one or more photovoltaic elements are disposed. In certainembodiments, a similar sidewall is provided at the right edge of thearea in which the one or more photovoltaic elements are disposed (i.e.internally adjacent the shiplap feature as described above with respectto FIG. 1). The frame structure is otherwise similar to that describedabove with respect to FIG. 1. In other embodiments, no sidewall isprovided at the right edge; the left-edge sidewall of an adjacent framestructure provides the fourth sidewall defining the area in which theone or more photovoltaic elements are disposed. In certain embodiments,the sidewalls extend above the upward-facing surface 135 of the area inwhich the one or more photovoltaic elements are disposed by at leastabout 1 mm, at least about 2 mm, or even by at least about 3 mm. Incertain embodiments, however, the sidewalls extend above theupward-facing surface 135 of the area in which the one or morephotovoltaic elements are disposed by no more than about 15 mm, no morethan about 10 mm, or even by no more than about 8 mm.

The photovoltaic roofing elements of FIGS. 1 and 1A can be arranged inan array, with laterally adjacent photovoltaic roofing elements beingengaged with one another in a shiplap manner. The photovoltaic roofingelement has on one side edge (in FIG. 1, the right-hand edge) anupward-facing water drainage channel. FIG. 2 is a cross-sectional viewof the photovoltaic roofing element of FIG. 1 in its exposure zone atits right hand edge, in which the frame structure 110, photovoltaicelement 170, and upward-facing channel 136 is visible. An outer flange137 defines the upward-facing water drainage channel. The upward-facingwater drainage channel is preferably open at the bottom edge of thephotovoltaic roofing element, such that any water entering the gapbetween adjacent photovoltaic roofing elements is collected therein andconducted down the roof. As shown in FIG. 2, the upward-facing channelis at a lower elevation with respect to the attachment zone. Thephotovoltaic roofing element has on its opposite side edge (in FIG. 1,the left-hand edge) a downward-facing flange (e.g., a ridge), configuredsuch that the downward-facing flange of one photovoltaic roofing elementcan engage the upward-facing channel of an adjacent photovoltaic roofingelement. FIG. 3 is a cross-sectional view of the photovoltaic roofingelement of FIG. 1 in its exposure zone at its left-hand edge, in whichtwo downward-facing flanges 138 are visible. These downward-facingflanges are configured to fit in the upward-facing water drainagechannel of an adjacent photovoltaic roofing element.

In certain embodiments, and as shown at the lower edge of thephotovoltaic roofing element of FIG. 1, a leading edge extension 140 isprovided to cover an upper portion of a photovoltaic roofing element ofan underlying course of photovoltaic roofing elements. When installed inan array, the leading edge extension 140 can extend substantially to theexposure zone of an underlying course of photovoltaic roofing elements,to improve conduction of water down the roof. In certain embodiments,the leading edge extension does not span the entire length of the framestructure; for example, as shown in FIG. 1, it can be missing in one ofthe sidelap portions, such that the leading edge extensions of adjacentphotovoltaic roofing elements do not interfere with one another. Incertain embodiments, the leading edge extension includes a recess on itsdownward-facing surface, to accommodate the raised lip 128 at the topend of the attachment zone of an overlying photovoltaic roofing element,thereby forming part of the water barrier system between the panels. Inuse, the leading edge extension can be covered by the one or morephotovoltaic elements; it need not be a visually distinct feature. Ofcourse, in other embodiments, the sidelap and shiplap features canextend the entire height of the frame structure, so that the entireheight of the side edges of adjacent elements interlock to one another.

FIG. 4 is another top schematic view of the photovoltaic roofing elementof FIGS. 1 and 1A with a rigid photovoltaic element (e.g., a moduleincluding the two rows of seven photovoltaic cells as described above,with a tempered glass top cover to protect the cells). Cells arelaterally spaced at intervals of about ¾ inch. The cells are inset fromthe top and bottom edges of the module by about ½ inch and from the leftand right side edges by about ⅜ inch. Preferably, the cells of themodule are inset from the edges of the module sufficiently to conform toUL, NEC or other electrical code requirements. The module is set intothe panel in the area formed by the sidewalls and sealed in place withan appropriate sealant, e.g., as a perimeter ridge surrounding themodule. The photovoltaic element (here, the module as defined by itstempered glass cover) will preferably be within 3 mm, within 2 mm, oreven within 1 mm of the sidewalls. Preferably, the ridge running alongthe top edge of the module provides a raised lip at the lower edge ofthe attachment zone and has drainage openings as described above toprovide drainage over the top surface of the module in the exposed areaof the photovoltaic roofing element.

In FIG. 4, the bottom edge of the photovoltaic roofing element is formedby the leading edge extension, but as described above, in someembodiments, no leading edge extension is at the bottom edge of thephotovoltaic roofing element. In either event, an indicator line isshown in FIG. 4 about ½ inch below the ridge at the bottom end of theattachment zone to suggest where the bottom edge of an overlyingphotovoltaic roofing element would lie in the installed condition. Thebottom edge of the overlying photovoltaic roofing element preferablycovers the horizontal-running seam where the photovoltaic element isdisposed in the frame structure (i.e., along the top sidewall). Windclips (as will be later discussed with reference to FIG. 9) are shown tobe attached using two of the nail boss fastening zones using the samefasteners to mount the panel to a roof structure; the wind clips canhold down the bottom edge of the overlying photovoltaic roofing element.In this embodiment, the drainage holes in the lower lip of theattachment zone are aligned with the nail bosses so that the wind clipspass through the drainage holes and provide an upward directed hook orclip to assist in securing an overlying course of photovoltaic roofingelements to the already installed lower course.

FIG. 5 is a partial schematic side view of a frame structure 510suitable for use in certain embodiments of the invention. A leading edgeextension 540 at the bottom side of the photovoltaic roofing element isat the left edge of the diagram; and the attachment zone 526 at the topside is at the right. The framing structure includes a downward-facingchannel 550 that can act as a wiring containment structure. In certainembodiments, and as shown in FIG. 5, a ridge 541 is formed on thedownward-facing surface of the framing structure 510 toward its bottomend. The ridge 541 is adapted to fit into a corresponding channel 542formed in the upward facing surface of an underlying panel, at theinterface between the attachment zone and the exposure zone. Theinterlocking of the ridge 541 into the channel 542 can provideadditional water resistance to an array of photovoltaic roofing elementsby providing a circuitous path for water, thereby preventing intrusionof water and wind-driven rain to the roof deck. The downward-facingsurface of framing structure of FIG. 5 also includes a wiringcontainment channel 550, into which wiring can fit, so that the framingstructure does not pinch it against the roof. Top and bottom sidewallsare not shown in the embodiment of FIG. 5, but could be included as theperson of skill in the art would realize in view of the presentdisclosure.

FIG. 6 is a top schematic view of the headlap portion and attachmentzone of an example of a photovoltaic roofing element, with emphasis on anumber of optional features that can help prevent water ingress. Theraised fastener locations can minimize water leakage around the nail orscrew used to attach the photovoltaic roofing element to a roof. The topsidewall (i.e., the “water barrier ledge” in the figure) acts as a wallor dam to minimize infiltration of wind driven rain. The ledge in thiscase also serves to define the location of edge of the exposure areaand, in certain instances, can cooperatively interact with an overlyingphotovoltaic roofing element to ensure proper location of the nextcourse (e.g., as described above with respect to FIG. 5). The drainageslots in the water barrier ledge are angled to prevent water being blownup into the attachment zone, while providing an exit path for water thatmay enter the attachment zone. Water exiting through the drainage slotsor weep holes would proceed down the roof over the top of the exposurearea of the photovoltaic roofing element. In certain embodiments, atleast one lateral side edge of the attachment zone does not include asidewall, such that water in the attachment zone can flow off of theside thereof (e.g., into a channel formed by a shiplap feature asdescried above). In other embodiments, a lateral side edge sidewallincludes drainage channels to allow water to drain off the side of thephotovoltaic element. In the embodiment shown in FIG. 6, the lateralsides of the attachment zone are not dammed off, such that any waterthat does make it into the attachment zone can to drain into thephotovoltaic roofing element's shiplap drainage channels. Water exitingto the right side of the photovoltaic roofing element shown woulddirectly enter its own drainage channel. Water exiting to the left sidewould enter the drainage channel of the left adjacent photovoltaicroofing element. In certain embodiments, similar drainage can beachieved if the sidewalls do not extend beyond the top surface of thephotovoltaic element.

FIG. 7 shows a top plan view of a photovoltaic roofing element similarto those of FIGS. 1, 1A and 2, but where the size and shape of theexposure zone has been adjusted to accommodate a photovoltaic modulehaving two rows of six inch photovoltaic cells. The configuration ofFIG. 7 has a greater surface area of active photovoltaic media than thatof FIGS. 1, 1A and 2. Of course, the person of skill in the art willappreciate that a variety of configurations and spacings of photovoltaiccells and modules can be used in practicing certain aspects of thepresent invention. Moreover, the person of skill in the art willappreciate that a wide variety of photovoltaic cells and modules can beused in practicing the present invention. The embodiments of FIGS. 1, 2and 7 are described as using rigid photovoltaic elements. In otherembodiments according to certain aspects of the invention, thephotovoltaic elements are flexible photovoltaic elements, for example,the encapsulated flexible photovoltaic elements available fromUni-Solar.

FIG. 8 shows a side edge view of a pair of roofing panels with a secondphotovoltaic roofing element 801 overlying a first photovoltaic roofingelement 800, disposed on a roof deck 890. An electrical connector 885(e.g., of the MC-4 type) is shown at the top of the first panel, itswiring contained in the wiring containment channel 850 at the top of thepanel (not visible in the first photovoltaic roofing element, butvisible in the second photovoltaic roofing element; see also FIG. 5).The thickness of the photovoltaic roofing element is sufficient tocontain the connector beneath the panel above the roof surface. Also, inthis view, the first course has a cant strip or starter block 895underlying the leading edge on the down roof side of the panel. The cantstrip raises the leading edge of the first course so that photovoltaicroofing elements of the first course are angularly oriented similarly tothose of the overlying courses.

FIG. 9 shows a top view and a side view of a wind clip leading edgeretainer for use with photovoltaic roofing elements according to certainembodiments of the invention. The wind clip can be mounted onto aselected nail boss of the attachment zone of a photovoltaic roofingelement, passing through a drainage slot, and providing an upwarddirected hook to secure the leading edge of an overlying photovoltaicroofing element. In one embodiment, the wind clips extend around tooutside of the leading edge of the overlying photovoltaic roofingelement, remaining visible in use. In another embodiment, the overlyingphotovoltaic roofing element (e.g., in its leading edge extension) isprovided with a slot at its bottom edge to accommodate passage of thewind clip therethrough. In another embodiment, the wind clips engagewith a recess in the downward facing surface of the photovoltaic roofingelement (e.g., in its leading edge extension) and are hidden from view.A preferred material for the wind clip is a metal such as aluminum ofabout 40 mil thickness. In the case where the clip hooks under theleading edge extension, preferably the angle of the bend in the clipsubstantially matches the exterior angle of the bottom edge of theoverlying photovoltaic roofing element. For a wind clip that engages afeature in the downward-facing surface of an overlying photovoltaicroofing element, the angle preferably substantially matches the geometryof the recess. For visible wind clips of aluminum, preferably the clipis colored either by coating, or alternatively by anodizing, to a colorto be complementary to the framing structure of the photovoltaic roofingpanel. Alternatively, wind clips could be made from polymeric or plasticmaterials. In some embodiments, selected wind clips can includeplatforms that act as snow guards to break up sliding snowfalls from theroof.

As described above with respect to FIG. 1A, in certain embodiments, theexposure zone includes raised sidewalls that define the area in whichthe photovoltaic elements are disposed. The area of the frame in whichthe one or more photovoltaic elements are disposed includes anupward-facing base surface 135, forming the base on which thephotovoltaic elements are disposed, and the sidewalls extend above theupward-facing surface 135 by at least about 2 mm, or even by at leastabout 3 mm. Advantageously, the sidewalls can enable an adhesive used toadhere the photovoltaic element to the frame to encapsulate part of theedge of the photovoltaic element, thus sealing and protecting it andreducing potential susceptibility to moisture intrusion.

An example of this effect is shown in partial cross-sectional schematicview in FIGS. 10A and 10B. In FIG. 10A, frame structure 1010 includes asidewall 1030 at its edge, which extends from the base surface 1035. Abead of adhesive sealant 1080 has been applied inside the sidewall, anda photovoltaic element 1071 is provided ready to be assembled to theframe to produce a photovoltaic roofing element. In this embodiment, thephotovoltaic element is in the form of a laminate (i.e., shown as aplurality of layers, including a layer of photovoltaic cells 1074encapsulated by polymer films 1073 (e.g., EVA films) to a back sheet1075 and a transparent cover (e.g., glass) 1072). In FIG. 10B, thephotovoltaic element has been disposed on the frame inside the sidewall.The bead of adhesive is squeezed to flow, filling the space between theframe surface and the laminate, making contact with both so as to bondthe laminate to the frame. In FIG. 10B, the flow of the adhesive aroundthe corner edge of the photovoltaic element proceeds up its side edge,but is contained in its flow by the sidewall of the frame structure.This can be contrasted with the situation shown in FIG. 10C; in theabsence of sidewalls, the adhesive can flow laterally away from thephotovoltaic element, and insufficiently seal in the edge of thephotovoltaic element. As shown in FIG. 10C, without a sidewall, the edgeinterfaces of the photovoltaic laminate structure can remainunencapsulated, thus leaving them susceptible to moisture intrusion andpossible detrimental effects on performance of the module over time whenexposed to weather and the environment.

In certain embodiments, the height of one or more of the sidewalls issuch that, when the photovoltaic element is installed, it is somewhatlower (i.e., in the plane of the photovoltaic element) than the topsurface of the photovoltaic element in at least some portions. This isillustrated in FIG. 10B, in which the sidewall is slightly lower thanthe top surface of the sidewall, such that water can drain down the rooffrom the top surface of the photovoltaic element. For example, incertain embodiments, the sidewall at the bottom edge of the framestructure is lower than the top surface of the photovoltaic element. Inother embodiments, the sidewalls at the bottom edge and one or more ofthe side edges are lower than the top surface of the photovoltaicelement. For example, in certain such embodiments, the sidewalls arelower than the top surface of the photovoltaic element by an amount inthe range of about 0.1 mm to about 5 mm, or in the range of about 0.25mm to about 2 mm.

In certain embodiments, the base surface of the area on which thephotovoltaic element is disposed includes one or more raised structures,on which the photovoltaic element rests. Thus, in such embodiments,there remains a fixed space between the downward-facing surface of thephotovoltaic element and the upward-facing surface of the base of theframe, such that an adhesive layer of a controlled thickness can beformed.

An example of such a frame structure is shown in perspective schematicview in FIG. 11. In the embodiment of FIG. 11, frame structure 1110includes sidewalls 1130, which enclose the area in which a photovoltaicelement is to be disposed, which area includes base surface 1135.Extending upwards from the base surface are raised structures 1137.Desirably, the raised structures are formed on less than about half ofthe base surface. In this embodiment, the base surface also has a holeor depression 1138 formed therein, through which fasteners can affix theframe structure to a roof surface. The raised structures can positionthe photovoltaic element at a selected height above the base surface ofthe frame structure, thereby providing a reproducible thickness orvolume of sealant or adhesive beneath the perimeter of the photovoltaicelement. It can also allow space for adhesive to flow upward at the edgeof the photovoltaic element to help ensure the sealing of thephotovoltaic element at the sidewall. In embodiments in which no raisedstructures are provided (see, e.g., FIG. 10B), care should be taken toensure that an appropriate amount of adhesive is used uniformly aroundthe frame and that the photovoltaic element is placed with uniform evenpressure so that adhesive can bond the photovoltaic element to theframe, sealing the panel, and avoiding uneven squeezing of the adhesive.If the pressure or adhesive amounts are not adequately controlled, someportions of the perimeter may have insufficient sealant, and/or thephotovoltaic element may become misaligned in the frame structure duringassembly. The use of raised structures can thus simplify the assemblyprocess. The use of raised structures can also help with repeatabilityof the assembly process, ensuring that all photovoltaic elementsprotrude substantially the same amount from the frame structure.

The use of a raised structure is illustrated in cross-sectionalschematic view in FIG. 12. The photovoltaic element 1271 is disposed onthe frame structure 1210 inside the sidewall 1230. When the bead ofadhesive 1280 is squeezed to flow, the photovoltaic element rests on theraised structures 1237, spaced from the base surface 1235. The adhesivefills the space between the base surface and the photovoltaic element,making contact with both so as to bond the laminate to the frame asdescribed above with reference to FIG. 10B. As noted briefly above, theraised structures provides a gap between the downward-facing surface ofthe photovoltaic element and the base surface of the frame structurealong the perimeter, and the sidewall contains the adhesive and helpsits flow direction to seal the edge of the photovoltaic element.

The height of the one or more raised structures can be selected toprovide for an appropriate volume of adhesive between the photovoltaicelement and the frame structure. In some embodiments, the one or moreraised structures are greater than about 10 mils in height, greater thanabout 20 mils in height, greater than about 30 mils in height, greaterthan about 40 mils in height, or greater than about 50 mils in height.In one particular embodiment, the height dimension of the raisedstructure is about 40 mils. In certain embodiments, the one or moreraised structures are less than about 200 mils in height, less thanabout 150 mils in height, or less about than 100 mils in height.

In the embodiment of FIG. 12, the raised structures are formed as adiscontinuous series of features (here, pedestals). In otherembodiments, the raised structures are formed as one or more continuous(or substantially continuous) ridges. For example, in the embodiment ofFIG. 13, a frame structure has raised ridges 1337 along the perimeter ofthe area in which the photovoltaic element is to be disposed. In thisembodiment, additional raised structures (in the form of ridges 1339)are disposed along the interior of the area in which the photovoltaicelement is to be disposed (here, along the support ribs) in order tosupport the photovoltaic element in the event of surface loading. When aphotovoltaic element is to be installed, a sealant or adhesive can beapplied along the perimeter of the area in which the photovoltaicelement is to be disposed, inside the sidewalls and outside the raisedstructures. The raised structures can thus form a channel or moat intowhich adhesive can be disposed. As described above, when thephotovoltaic element is disposed within the frame, it rests on theraised ridge structures, squeezing a portion of the adhesive or sealantso that it flows upwardly at the edges and is contained by the sidewallsof the frame structure.

FIG. 14 shows a side cross sectional schematic view of an embodiment ofa photovoltaic roofing element as assembled. A frame structure 1410(formed from polymer) holds a photovoltaic element 1470 in laminateform. The laminate structure includes crystalline silicon-basedphotovoltaic cells encapsulated by an ethylene vinyl acetate (EVA)-basedadhesive and protected with a glass cover sheet and a polymeric backsheet, as more generally described above with reference to FIG. 10A. Araised structure 1437 supports the module a set distance from the framestructure. An adhesive 1480 fills the gap in selected areas between themodule and the frame. One adhesive that can be utilized is known asadhesive 804 Dow Flexible Adhesive provided by the Dow Chemical Companyof Midland, Mich. In certain embodiments of the invention, and as shownin FIG. 14, a second adhesive or caulking material 1482 is included forsealing the edge of the photovoltaic laminate assembly in the frame. Thesecond material 1482 may be different from or the same as the firstadhesive. In particular, moisture cure or two component cure systems canbe useful for sealing the edges of the photovoltaic element.

As noted above, in certain embodiments, the height of one or more of thesidewalls is such that, when the photovoltaic element is installed, itis somewhat lower than the top surface of the photovoltaic element in atleast some portions. In certain such embodiments, the sidewall adjacentthe top edge of the frame structure has a height such that, when thephotovoltaic element is installed, it is somewhat higher (i.e., in theplane of the photovoltaic element) than the top surface of thephotovoltaic element, at least in some portions. Such an embodiment isshown in cross-sectional schematic view (i.e., looking across the roofsurface) in FIG. 15. In FIG. 15, bottom edge sidewall 1531 is lower thanthe upward-facing surface of the photovoltaic element 1570; while thetop edge sidewall 1532 is higher than the upward-facing surface of thephotovoltaic element 1570. Notably, a wind clip 1590 sits on the topedge sidewall 1532, and does not contact the top surface of thephotovoltaic element, thus minimizing damage to the photovoltaic element(e.g., via scratching resulting from movement of the wind clip relativeto the photovoltaic element due to wind).

As noted above, in certain embodiments of the invention, the raisedstructures are discontinuous. Accordingly, in use, adhesive is notconfined within a “moat” formed by the raised structure, and can flowthrough the discontinuities to adhere the photovoltaic element to theframe structure in more internal areas. FIG. 16 is across-sectional/perspective partial schematic view of a frame structurehaving a discontinuous raised structure. When a photovoltaic element isinstalled into this frame structure with an adhesive as described above,the adhesive flows not only up the sidewall, but also through thediscontinuity to occupy additional space between the frame and thelaminate, internal relative to the raised structures. The dashed lineshows an example of the extent of adhesive flow. Accordingly, adiscontinuous set of raised structures can provide greater surface areaof bonding between the photovoltaic element and the frame structure.

In certain embodiments, a raised structure is positioned in contact witha sidewall. One such embodiment is shown in partial cross-sectionalschematic view in FIGS. 17A and 17B. In FIG. 17A, a bead of adhesive1780 is applied on the raised structure 1737, which is disposed incontact with the sidewall 1731. Photovoltaic element 1770 is positionedover the frame structure, ready to be pushed down onto the adhesive. InFIG. 17B, the photovoltaic element has been pushed onto the raisedstructure, and the adhesive flows into the space between the edge of thephotovoltaic element and the sidewall and the area inside the raisedstructure to bond the parts to one another.

FIGS. 18A, 18B and 18C are partial schematic end views (withcross-sectional detail in dashed line) of photovoltaic roofing elementsaccording to various embodiments of the invention. The bottom end ofeach is on the left of each figure; and the top end is on the right.Attachment zones are not shown in these figures. In all of FIGS. 18A,18B and 18C, the bottom edge sidewall is slightly lower than the topsurface of the photovoltaic element (i.e., in the plane of thephotovoltaic element). In FIG. 18A, the right edge sidewall (i.e.,disposed to the front) tapers from top edge to bottom edge so that atleast portions of the edge sidewall are lower than the top surface ofthe photovoltaic element when installed in the frame structure. Havingthe bottom and edge sidewalls lower than the top surface of thephotovoltaic element allows for drainage of water off of thephotovoltaic roofing element in use. In FIG. 18B, the right edgesidewall is the same height as the bottom edge sidewall with a distincttransition in height near the top end of the part of the frame structurecontaining the photovoltaic element. In FIG. 18C, there is a smoothtransition in right edge sidewall height near its top end.

In certain embodiments, the frame structure is formed from a pluralityof horizontally-adjacent pieces. The frame structure can, for example,be assembled from separate pieces on the roof, with the separate pieceson the roof together providing the sidewalls forming a substantiallyclosed polygon. Such a frame structure can be assembled with a singlephotovoltaic element covering both pieces of the frame structure. Thepieces can be joined with an expansion joint in their area of overlap,the expansion joint designed to offset differences in thermal expansionbetween the frame structure and the photovoltaic element (e.g.,especially when the photovoltaic element is formed with a glassprotective sheet). The expansion joint can be formed, for example, byshiplap features that have play in them, such that the two horizontallyadjacent pieces can move somewhat with respect to one another. Anexample is shown in cross-sectional schematic view in FIG. 19. Framepieces 1913 and 1915 interlock to form a single frame structure that isconfigured to hold a photovoltaic element within sidewalls 1931 and1932. The shiplap features do not fit tightly, but rather leave someroom for the pieces to shift horizontally. In the embodiment of FIG. 19,a flexible sealant 1980 seals the pieces to one another while allowingthem to move with respect to one another to accommodate expansion orcontraction differences due to temperature.

FIG. 20 is a perspective view of a frame structure for a photovoltaicroofing element. The area for receiving a photovoltaic element has aribbed structure to provide strength to the geometry of the frame. Asidewall is provided at the bottom, top, and each side edge of the areafor the photovoltaic element. A raised structure is provided inside thesidewalls, creating a moat for receiving and guiding the flow of asealing adhesive used to bond a photovoltaic element to the framestructure; and for providing support to the photovoltaic element. Theraised structure is also present on a portion of the ribbed structuresin the central part of the frame structure to aid in minimizing flexureof the photovoltaic element in an assembly. The top portion of the framestructure includes an attachment zone with protruding nail bosses forfastening the shingle to a roof. Recesses are provided in the top edgesidewall to accommodate wind clips that may be attached with fastenersthrough the nail bosses. Additional recesses are provided in the lowerlip of the leading bottom edge of the frame structure to accommodatewind clips attached to a next lower course of photovoltaic roofingelements on a roof. Wire retaining features are provided at the upperedge of the frame above the fastening zone. Right and left sides of theframe structure include ship lap interlocking features to closelaterally adjacent photovoltaic roofing elements between shingles in anarray and direct water down the roof, as described herein.

FIG. 21 is a bottom view of the frame structure of FIG. 20. Distributedacross the underside of the frame are support legs (in a “bullnose”shape in this embodiment) to bring the frame structure into contact withthe roof deck as photovoltaic roofing elements are laid in anoverlapping fashion in an array. The legs closer to the bottom edge ofthe photovoltaic roofing array are taller than the legs closer to thetop edge. The bottom edge does not have the legs, as it is intended torest atop the fastening zone of a photovoltaic roofing element in thenext lowermost course or a cant strip or starter strip. The legsmaintain a space beneath the shingle to aid in wire management.

FIG. 22 is a perspective view of an assembled photovoltaic roofingelement including a frame structure as described in FIG. 20. Thephotovoltaic roofing element in this embodiment includes the frame, aphotovoltaic laminate, fasteners and wind clips. FIG. 23 is an explodedisometric view of the photovoltaic roofing element of FIG. 22, showingthe frame structure, the photovoltaic element, wind clips and fastenersin a separated fashion.

FIGS. 24A and 24B top and bottom perspective schematic views,respectively, of a starter strip for use with the lowermost course of anarray of the photovoltaic roofing elements of FIG. 22. The starter striphas recesses for receiving ridge structures beneath the lower leadinglip of the frame of an overlying photovoltaic roofing element as shownin FIG. 21. Since the photovoltaic roofing elements in an arraygenerally overlap a fastening zone of a photovoltaic roofing element ina lower course in an array and are slightly canted on the roof, thestarter strip or cant strip serves to raise the bottom edge of thephotovoltaic roofing elements in the lowermost course so that all of thephotovoltaic roofing element in the array are similarly angularlyoriented, and closes the leading edge of the array. The leadingdown-roof edge may serve as a retaining clip for engaging the lower lipof an overlying photovoltaic roofing element. Optionally, not shown,recesses may be provided in the starter strip to accommodate wind clipsfor further securing the lower edge of an overlying photovoltaic roofingelement. Moreover, while the starter strip of FIGS. 24A and 24B is shownas being substantially solid, in other embodiments it is at leastpartially hollow in cross-section. Starter strips (both solid and atleast partially hollow) can be made via extrusion,

FIG. 25 shows a small array of the photovoltaic roofing elements of FIG.22. The array of FIG. 25 is two photovoltaic roofing elements wide andfour photovoltaic roofing elements high. It includes starter strips.Side and top flashing (not shown) can be provided as described in U.S.Provisional Patent Application Ser. No. 61/429,053 (and as described inmore detail below), to close the array at the sides and top and mergethe photovoltaic array into a field of surrounding conventionalshingles.

Certain aspects of the invention relate to the fashion in which flashingelements are provided to close the transition that merges a photovoltaicarray made up of photovoltaic roofing elements into the field ofconventional roofing products used in conjunction with the photovoltaicroofing elements. Flashing elements as installed together with a smallarray of photovoltaic roofing elements (frame structures shown) areshown in perspective view in FIG. 26.

Accordingly, one aspect of the invention is a photovoltaic roofingsystem disposed on a roof deck having a top end (i.e., toward the ridgeof the roof) and a bottom end (i.e., toward the eave of the roof). Thephotovoltaic roofing system includes one or more photovoltaic roofingelements contiguously disposed on the roof deck, thecontiguously-disposed roofing elements together having a top edge facingthe top end of the roof deck, a bottom edge facing the bottom end of theroof deck, and two side edges. Each photovoltaic roofing elementcomprises one or more photovoltaic elements disposed on a framestructure. The frame structure includes sidelap portions havinggeometries adapted to interlock with adjacent photovoltaic roofingelements to provide water drainage channels. The photovoltaic roofingsystem also includes a plurality of roofing elements disposed adjacentthe contiguously-disposed photovoltaic roofing elements, along theirside edges. The photovoltaic roofing system further comprises sideflashing elements disposed along the side edges of thecontiguously-disposed photovoltaic roofing elements, the side flashingelements having a cross-sectional shape comprising avertically-extending feature and a flange extending away from a lateralside at the downward end of the vertically-extending feature, with theflange facing away from the contiguously-disposed photovoltaic roofingelements and being at least partially disposed between a roofing elementand the roof deck. The vertically-extending feature includes a matchedinterlocking geometry adapted to interlock with the sidelap portion ofan adjacent photovoltaic roofing element. For example, in certainembodiments, the vertically-extending features of the side flashingelements along a first lateral edge of the contiguously-disposedphotovoltaic roofing elements include a downward-facing flange, disposedin upward-facing channels of the photovoltaic roofing elements disposedalong the first lateral edge; and wherein the vertically-extendingfeatures of the side flashing elements along a second lateral edge ofthe contiguously-disposed photovoltaic roofing elements include anupward-facing water drainage channel, into which downward-facing flangesof the photovoltaic roofing elements disposed along the second lateraledge are disposed.

Preferably a top flashing and/or a bottom flashing are also included tomerge the photovoltaic roofing system with a field of conventionalroofing products and close the transition areas therebetween to theelements. Accordingly, in certain embodiments, one or more top flashingelements is or are disposed along the top edge of thecontiguously-disposed photovoltaic roofing elements, the one or more topflashing elements having a bottom end disposed over the top edge of thecontiguously-disposed photovoltaic roofing elements; and a top enddisposed under one or more roofing elements disposed along the top edgeof the contiguously-disposed photovoltaic roofing elements.

FIGS. 27, 28 and 29 show top schematic views and edge schematic views ofexamples of top flashing elements for closing the top portion of thearray of photovoltaic roofing elements according to one embodiment ofthe invention. In these figures, the top plan views depict the leftmostside of a given flashing section near the top of the drawing and therightmost side near the bottom of the drawing. In FIG. 11, the lineal orstandard piece for flashing the array, but not at an edge of the array,has hidden lap alignment features. At the left end of the flashingelement, a portion is thinned for a distance on the bottom of the piece,dashed lines indicating the thinning on the bottom. At the right end,the thinning is at the top. When adjacent flashing elements areinstalled across the array, the left end overlaps the right end of anadjacent section of flashing. The thinning of the end provides anindicator for proper lateral overlap at the end. From left to right inFIG. 27, the flashing has three zones. The two left zones go up and overthe upper edge of the topmost course of the photovoltaic roofing panelsin the array. The right portion is flat on the roof deck. Conventionalroofing materials are installed so that they overlap at least the rightuppermost portion of the top flashing to direct moisture down the roof.In some instances, the exposure zone of a conventional roofing productmay extend to cover the majority, or completely cover, the top flashingelements across the photovoltaic roofing product array. FIG. 28 showsviews of a right end top flashing element. The upper flat flange in theplane of the roof deck extends around to the right end beyond the raisedbend feature. FIG. 29 shows views of a left end top flashing element,the flashing flange extending around to the left. The raised bendfeature covers the top edge of the photovoltaic roofing array. Theflanges underlie adjacent conventional roofing materials. The flashingscan be formed from a variety of materials; for example, they can bemolded or formed from plastic or metal.

FIG. 30 is a set of schematic views (top, back, side and front) of aright side flashing element for use with photovoltaic roofing elementsof FIGS. 1, 1A and 2 according to one embodiment of the invention. Theright side flashing element is installed along the right edge of a setof contiguously-disposed photovoltaic roofing elements. It includes anoverlap portion 3010 and an exposed portion 3015. The top schematic viewof FIG. 30 has the uppermost portion of the right flashing at the lowerend of the figure. A cut-back notch 3020 is provided so that anoverlying right side flashing element can fit into the underlying piecewith a flush right edge. The side schematic view in FIG. 30 shows thatthe right side flashing element has a greater height at its lower end(left side of the side schematic view) than at its upper end, toaccommodate the canting of the photovoltaic roofing elements in thecourse as they overlie the underlying course. The front view (i.e.,looking up the roof) and the back view (i.e., looking down the roof)show downward directed ridges that interact cooperatively with theunderlying drainage channel at the right side edge of the roofing panelof FIG. 1. The downward directed structures are analogous to thestructures shown at the left edge of the photovoltaic roofing element ofFIG. 1. The right side flashing element engages with the right side edgeof the roofing panel in a shiplap fashion, with the flange (i.e.,overlap portion 3010) extending under adjacent conventional roofingmaterial to flash in and close the roof to the elements. In someembodiments, the flange extends at least about 2 inches, at least about4 inches, at least about 6 inches, or at least about 8 inches or moreunder the adjacent roofing materials. It will be understood that for usewith photovoltaic roofing elements of another dimension, the size andproportion of the right side flashing elements may be suitably adapted.

FIG. 31 is a set of schematic views (top, back, side, front andperspective) of a left side flashing element for use with photovoltaicroofing elements of FIGS. 1, 1A and 2 according to one embodiment of theinvention. The left side flashing element is installed along the leftedge of a set of contiguously-disposed photovoltaic roofing elements. Itincludes an overlap portion 3110 and an exposed portion 3115. The topview of FIG. 31 has the uppermost portion of the left side flashingelement at the lower end of the figure. A cut-back notch 3120 isprovided so that an overlying left side flashing element can fit intothe underlying piece with a flush left edge. The side view in FIG. 31shows that the left side flashing element has a greater height at itslower edge (at the right side of the figure) than at its upper end toaccommodate the canting of the photovoltaic roofing elements in thecourse as they overlie the underlying course. The front view of the leftside flashing element is taken looking up the roof and the back view istaken looking down the roof. The front view (i.e., looking up the roof)and the back view (i.e., looking down the roof) show the upward-directededge ridge and drainage channel that interact cooperatively with theoverlying downward-directed ridges at the left side edge of thephotovoltaic roofing element of FIGS. 1, 1A and 2. The upward directedridge and drainage channel are analogous to the structures shown at theright edge of the photovoltaic roofing element of FIG. 1. Preferably,the left side edge flashing is installed prior to installation of aleftmost photovoltaic roofing element in a course. The left side edgeflashing element engages with the left side edge of the photovoltaicroofing element in a shiplap fashion and provides a flange (i.e., theoverlap portion 3110) to extend under adjacent conventional roofingmaterial to flash in and close the roof to the elements. In someembodiments, the flange extends at least about 2 inches, at least about4 inches, at least about 6 inches, or at least about 8 inches or moreunder the adjacent roofing materials. It will be understood that for usewith photovoltaic roofing elements of another dimension, the size andproportion of the left side flashing elements may be suitably adapted.It will also be understood that if geometries of parts of the roofingsystem including photovoltaic roofing elements and flashing componentsare reversed, such as for example by mirroring, that preferred orders ofinstallation may also accommodate such changes.

FIG. 32 shows various schematic views of an embodiment of a cant strip3200 (e.g., a starter strip) according to one embodiment of theinvention. In use, the cant strip can be disposed under the bottom edgeof the contiguously-disposed photovoltaic elements and on top of anunderlying course of roofing elements. The cant strip can serve to closethe lower edge of an array of photovoltaic roofing elements. In the topviews, fastening holes 3210 are visible; these are provided to attachthe strip to a roof. An offset shape for dovetailing adjacent strips oneto another is provided to help minimize the potential for waterintrusion. The back view (i.e., down roof view) and front view (i.e., upthe roof) show internal support ribs in phantom. The side view shows arecess 3220 for receiving a locator ridge that would extend on thedownward-facing surface of the bottom end of an overlying photovoltaicroofing element. The side view shows that the height of the strip isgreater on the down-roof side and thinner on the up-roof side. The cantstrip serves to provide an angular deviation from the plane of the roofso that the lowermost course of photovoltaic roofing elements issubstantially plane parallel to successive courses. Accordingly, incertain embodiments, the thickness of the cant strip is substantiallysimilar to the thickness of an installed photovoltaic roofing element atits top end, as measured in a direction normal to the roof surface.

FIG. 33 is a pair of perspective views of cant strips in position undera photovoltaic roofing element as described with respect to FIGS. 1, 1Aand 2. Each cant strip 3201, 3202 is cooperatively engaged with thelowermost photovoltaic roofing element of an array. The cant strip 3201has a recess that interacts with a locator ridge on the downward-facingsurface of the lowermost photovoltaic roofing element 3301. The leadingedge of the cant strip is angled to match the angle of the photovoltaicroofing element and continue a downward slope for direction of water onthe roof. In the inset, cant strip 3202 has a locator ridge, whichinteracts with a recess formed in the downward-facing surface of thephotovoltaic roofing element 3302.

It will be noted that the downward-facing surfaces of the photovoltaicroofing elements of FIG. 33 (and other FIGS., including FIG. 26) have aplurality of downward-facing support structures, here, ribs formed in agrid structure. The downward-facing support structures serve to reducethe amount of material necessary to provide a supportive framestructure. They also provides a degree of rigidity to minimize flexingso that the photovoltaic elements are supported with minimal deformationstresses imparted; this can be especially important when rigidphotovoltaic elements are used. Moreover, thermal expansion andcontraction effects can also be balanced in part by such a structure.The ribbed structure can also provide locations for securing junctionboxes and electrical components for the photovoltaic elements held bythe frame structure. In the embodiment of FIG. 33, the supportstructures are intersecting ribs, but the person of skill in the artwill appreciate that other structures could be used.

As noted above, FIG. 26 is a top perspective schematic view of a partialassembly of photovoltaic roofing elements and flashing components. Thephotovoltaic roofing elements are similar to those of FIGS. 1, 1A and 2,the photovoltaic elements being shown as semitransparent. In the framestructures, the exposure area is underlied by slats (here,criss-crossing), spaced to support the photovoltaic elements, butallowing wiring to run from the downward-facing side of the photovoltaicelements to the downward-facing surface of the photovoltaic roofingelement, thereby protecting it from weather. In this embodiment, theslat structure also includes a square pad for the attachment of largerelectrical components, for example, a junction box for wiring togetherindividual photovoltaic elements and providing a single electricaloutput for the overall photovoltaic roofing element. In the array ofphotovoltaic roofing elements of FIG. 26, the individual photovoltaicroofing elements are laterally offset from one another; this offsetconfiguration provides a visual effect similar to some conventionalroofing materials. Shorter framing structures are included to fill inthe offset so that the array has common linear left and right edges.These fill pieces may include photovoltaic elements (not shown), or mayinclude another upper surfacing media (not shown) with a complementaryvisual appearance to the photovoltaic roofing elements and/or associatedconventional roofing elements to be installed therearound. Left sideflashing elements are included in the assembly of FIG. 26, applied in anoverlapping fashion and cooperatively engaged with the left edge of thephotovoltaic roofing elements as described above. A cant strip isprovided to raise the lower leading edge of the bottommost course ofphotovoltaic roofing elements as described above. Right side flashingelements are included to cooperatively engage the right side edges ofthe photovoltaic roofing elements as described above. It will be notedthat fastening locations for the side flashing elements are such that alower fastening location of each unit is suggested and that an upperfastening point is accomplished by successive fastening of the nextoverlying course flashing element. Top flashing elements are alsoincluded in the assembly of FIG. 26. The top right end flashing elementincludes the flange to the right to underlie adjacent conventionalroofing elements, and includes raised bend portions to step up and ontothe contiguously-disposed photovoltaic roofing elements at the edgethereof. In this instance, the right top end flashing element overlapsthe center top flashing element with a hidden alignment overlap. In thisinstance, the top flashing elements are depicted with fastening slots.With slots it may be desirable to fasten the pieces to the roof in anon-hardnailing manner so that larger pieces may move laterally toaccommodate thermal expansion and contraction. It will be understoodthat in certain instances, an alignment undercut or thinning may beomitted, in which case, it may be desirable for the flashing elements tofloat freely analogously to conventional vinyl siding to accommodatethermal expansion and contraction in use. It will be also understoodthat in a wider array including a greater number of photovoltaic roofingelements, a larger number of top center flashing elements may beemployed. A left top end flashing element is not shown in FIG. 26, butthe person of skill in the art would understand that a full assembly caninclude one.

FIG. 34 is a schematic top view of a photovoltaic roofing system, inwhich a rectangular array of contiguously-disposed photovoltaic roofingelements as described above is installed on a roof with conventionalmetric three-tab shingle of 13¼″×39⅜″ dimension and 5⅝″ exposure. Eachphotovoltaic roofing element 3400 includes 2 rows of 6 six-inch squarephotovoltaic elements. The photovoltaic roofing elements are offset byusing shorter photovoltaic roofing elements 3401 at alternate ends ofthe courses, each shorter photovoltaic roofing element having 2 rows of2 photovoltaic elements. In some embodiments an offset is preferred sothat continuous alignment of a large number of drainage channels in theshiplap portion of the photovoltaic roofing elements does not occurvertically up the array. The offset of the photovoltaic roofing elementsenables a lateral offset of the drainage channels at the right side edgein the ship lap portion of the photovoltaic roofing element so thatdrainage can occur over the face of underlying courses of photovoltaicroofing elements. In this way, in heavier rain situations, overloadingof aligned drainage channels is avoided. The shorter fill panels includeall of the edge features of the larger photovoltaic roofing elements.Sections of cant strip (not shown) are included along the lower edge ofthe array. Left side edge flashing (not shown) is provided along theleft edge of each course of photovoltaic roofing elements in the array.Right side edge flashing (not shown) is provided at the right edge ofeach course of photovoltaic roofing elements. Top flashing (not shown)with molded edge flashing for the ends of the array is included acrossthe top of the array and covered by overlying shingles.

FIG. 35 shows a diagonally stepped array of photovoltaic roofingelements on a roof of three-tab shingles. The offset provides thedrainage features as noted above. In this array, the left end of eachcourse includes a left side flashing unit and a short piece of left endtop flashing unit to flash in the diagonal step up the array and closethe roof for drainage. Right side edge flashing and cant strips areprovided at the right end of each course.

FIG. 36 depicts an alternative side flashing configuration, in which oneor more side flashing elements is configured such that a conduit isformed underneath the side flashing element and adjacent the framestructure of the photovoltaic roofing element with which it interlocks.Frame structure 3600 includes an upward-facing water drainage channel3605. Side flashing 3610 includes a vertically-extending feature 3612which has a downward-facing flange 3615, which fits into upward-facingwater drainage channel 3605. Side flashing also includes a flange 3618extending away from the frame structure, on which a roofing element(here, a shingle 3620) is disposed. Notably, the vertically-extendingfeature also extends horizontally (shown by ref. no. 3613) sufficientlyto form a conduit 2030 adjacent the frame structure. Wiring 3635 isshown disposed in the conduit. Accordingly, the flashing can act as aconduit to track the wiring up or down a side of an array to aconvenient location for wire take off from the roof or, in certaininstances, a convenient location for a roof penetration.

FIG. 37 is a perspective view of an alternative side corner flashing foruse in a stepped diagonal array with an offset in the photovoltaicroofing elements (e.g., as shown in FIG. 35). In this case the waterdrainage channel 3705 directs moisture downward on the roof over anunderlying course of shingles and a horizontal flange 3720 extendsfurther over an attachment zone of a panel of the underlying course sothat it may be flashed in with conventional roofing products.

FIG. 38 depicts a roof in which the contiguously-disposed photovoltaicroofing elements 3800 are to fit into an area with diagonal sides.Inserts 3830 with an angled side are provided that have appropriate sideinterlocks and drainage channels to fit in with the photovoltaic roofingelements of the array. A variety of angled parts (e.g., 3831, 3832,3833) that interlock into the roofing panels may be provided to fitdifferent angular roofing situations.

In some embodiments, as shown in FIG. 39 in partial schematic view, oneor more diagonal ridges are disposed in the attachment zone. Theridge(s) are disposed such that, when the photovoltaic roofing elementis installed, they are sloped toward the bottom end thereof, such thatwater entering the attachment zone may traverse down to a drainage holeor channel and then out over the top surface of the exposure area, andthen down the roof. In FIG. 39, ridge 3910 is disposed at a diagonalwith respect to the horizontal axis of framing structure. Drains or weepholes 3930 may also be provided periodically along the length of adiagonal water dam in the attachment zone as depicted in FIG. 39.

FIG. 40 is a schematic cross-sectional view of a ridge 4010 with a drainchannel 4020 in phantom. The ridge is one configuration for a first damin an attachment zone above the exposure zone of a roofing element. Anywater intrusion into the attachment zone can be directed downward andout through the drain opening or to the edge of the photovoltaic roofingelement and down the water drainage channel at the side. FIG. 41 is across-sectional view of another configuration, in which a photovoltaicelement 4130 is present in the exposure area on the downward side of theridge 4110 (left in the figure). The top planar surface of thephotovoltaic element is above the plane of the attachment area higher upthe roofing panel. In the drain slot 4120 through the ridge of FIG. 41,the base of the slot (shown in phantom) is at or slightly above the sameplane as the top surface of the photovoltaic element, such that waterflows across the photovoltaic element, instead of underneath it. Thesurface 4140 of the attachment zone is tapered upwards, such that wateris delivered to the drain slot. One benefit of the ramp structure isthat water would be delivered over the surface of the photovoltaicmodule and away from sealed joint between the photovoltaic element andthe frame structure. FIG. 42 is a schematic cross-sectional view ofanother modification of the drainage system, with the base plane 2640 ofthe attachment zone at a level even with or above the plane of thephotovoltaic element 4230 so that water is delivered from the attachmentzone over the photovoltaic element below without the need for a ramp ortaper. The ridge structures of FIGS. 40, 41 and 42 can be used, forexample, as a ridge at the bottom end of the attachment zone asdescribed above with respect to FIG. 1.

FIG. 43 is a cross-sectional view of a portion of a frame structureequipped with a photovoltaic element. The frame structure 4300 includes,at the top end of the exposure zone, a receiver flange 4310 whichsecures the upper edge of the photovoltaic element 4320. The attachmentzone is shown in phantom by reference numeral 4330. Sealant 4340 isdepicted around the perimeter of the photovoltaic element to seal thephotovoltaic element to the frame structure.

In FIG. 44, another embodiment of a frame structure equipped with aphotovoltaic element is shown in partial perspective view. A receiverflange 4410 is provided at the top edge of the frame structure 4400 asdescribed with respect to FIG. 43. In the embodiment of FIG. 44, a damstrip 4430 is disposed on the upward-facing surface of the photovoltaicelement 4420, above the top of the active area of the photovoltaicelement. The dam strip is raised from the surface of the photovoltaicelement, and can cooperate with a recess on the underside of the leadingedge of an overlying photovoltaic roofing element to aid in closure ofthe system to moisture. The dam strip can be applied to the surface ofthe photovoltaic element after it is installed. In one embodiment, thedam strip is installed with a gentle angle, with one end of the damstrip closer to the top end of the photovoltaic roofing element than theother, in order to guide any moisture that would intrude over the dam tothe water drainage channel at the side edge of the roofing panel.Optionally, the dam strip may comprise a sealant to close the system towater.

In certain embodiments, the frame structure is rigid. Suitable materialsfor the framing structure include polycarbonate and other polymers.Filled polyolefins such as polypropylenes and copolymers or polyvinylchloride, CPVC, ASA or AES can be used for the various flashingcomponents. Parts can be made by extrusion followed by forming such assizing or vacuum forming, depending on the polymer and its flowproperties, or by molding processes such as injection molding orcompression molding. Filled polymers and composites with low thermalexpansion coefficients are preferred.

A photovoltaic roofing system has been described that can integratephotovoltaic roofing elements with conventional roofing products. Thesystem can provide edge, top and bottom closure for the roof against theelements. Lateral interlocks and drainage channels can contribute to theclosure of the roof. Ridges and grooves can provide tortuous pathways toinhibit moisture transgression into the roof. Raised nail bosses orfastening points can provide another level of difficulty for moistureentry through the roof. Aspects that are useful for the prevention ofentry of wind driven rain can also be useful for electricalconsiderations in maintaining electrical components in a dryenvironment.

The canted or extended leading edge of the photovoltaic roofing elementsdescribed herein can provide for easy downward flow of moisture on theroof. If moisture intrusion occurs in the attachment zone, a ridgestructure with weep holes for drainage can inhibit further intrusion ofthe moisture. A ridge near the top edge of the attachment zone canprevent overflow of the attachment zone and helps direct moisture todrainage channels. In some cases the downward-facing surface of theleading edge of the photovoltaic roofing element includes recesses thatcan receive the ridges and further assist in directing moisture down theroof.

In preferred photovoltaic roofing systems the parts are available inmodular components that fit together and can be kitted in advance tominimize the need for fabrication on site. For example, flashingcomponents and cant strips, in this instance, are provided in lengthsthat are integral multiples of the dimensions of the photovoltaicroofing elements or partial photovoltaic roofing element sizes toaccommodate predetermined arrays for the roofing system in dimensionsand power ratings suitable for a particular roofing project.Accordingly, assembly on the roof can be simplified.

Any cabling or wiring interconnecting the photovoltaic roofing elementsof the invention in a photovoltaic roofing system can, for example, belong and flexible enough to account for natural movement of a roof deck,for example due to heat, moisture and/or natural expansion/contraction.The cabling or wiring can be provided as part of a photovoltaic roofingelement, or alternatively as separate components that are interconnectedwith the photovoltaic roofing elements (e.g., through electricalconnectors) during installation.

Examples of electrical connectors that can be suitable for use oradapted for use in practicing various embodiments of the invention areavailable from Kyocera, Tyco Electronics, Berwyn, Pa. (trade nameSolarlok) and Multi-Contact USA of Santa Rosa, Calif. (trade nameSolarline). U.S. Pat. Nos. 7,445,508 and 7,387,537, U.S. PatentApplication Publications nos. 2008/0271774, 2009/0126782, 2009/0133740,2009/0194143 and 2010/0146878, each of which is hereby incorporatedherein by reference in its entirety, disclose electrical connectors foruse with photovoltaic roofing products. Of course, other suitableelectrical connectors can be used. Electrical connectors desirably meetUNDERWRITERS LABORATORIES and NATIONAL ELECTRICAL CODE standards.

In certain embodiments, the photovoltaic roofing elements of the arrayare electrically interconnected. The interconnected photovoltaic arraycan be interconnected with one or more inverters to allowphotovoltaically-generated electrical power to be used on-site, storedin a battery, or introduced to an electrical grid. For example, a singleinverter can be used to collect the photovoltaically-generated power andprepare it for further use. In other embodiments, the photovoltaicroofing elements can be interconnected with a plurality ofmicro-inverters disposed on the roof. For example, a singlemicro-inverter can be used for each photovoltaic roofing element; or asingle micro-inverter can be used for a group of photovoltaic roofingelements.

In certain embodiments of the invention, for example as described abovewith respect to FIGS. 5 and 8, the frame structure includes a wiringcontainment structure. The person of skill in the art can determine thelength and position of the wiring containment structure, depending, forexample, on the particular wiring scheme used for the overallphotovoltaic roofing system envisioned. In the embodiment of FIGS. 5 and8, the wiring containment structure is formed on the downward-facingsurface of the frame structure, thereby allowing wiring to be containedunder the frame structure. In another embodiment, shown incross-sectional view in FIG. 45, a frame structure 4500 includes aplurality of downward-facing support structures 4510. The framestructure also includes a wiring containment structure, here a channel4520, on the downward-facing surface of the frame structure.Accordingly, the wiring 4530 can be held in place such that it cannot beinadvertently pinched underneath the support structures.

In the embodiment of FIG. 45, the wiring containment structure is formedas a channel. In certain embodiments, and as shown in FIG. 45, the edgesof the opening of the channel can be somewhat more narrow than the restof the channel (and of the wiring to be contained therein), such thatthe wiring can “snap” in. In other embodiments, wiring can be held inthe channel in other ways, for example using an adhesive, or usingpost-applied retaining elements such as fasteners.

One embodiment of a framing structure is shown in cross-sectional viewin FIG. 46. The frame structure 4600 includes downward-facing supportstructures 4610 (in this embodiment, ribs are formed in a criss-crosspattern, as shown in FIG. 33). At least some of the downward-facingsupport structures can substantially contact the roof when installed.The frame structure also includes a wiring containment structure 4620that creates a path for wiring 4630 to run along the downward-facingsurface of the frame structure, without being caught between thedownward-facing support structures and the roof deck. In thisembodiment, the wiring containment structure is a series of holes ornotches (shown in phantom) cut in the downward-facing supportstructures; wiring can traverse the downward-facing surface of thethrough the holes or notches. The wiring containment structure can, forexample, run from the junction box to the top end of the framestructure, then to the corner of the frame structure for attachment toan adjacent photovoltaic element, for example as shown in FIGS. 5 and 8.

The frame structure of FIG. 46 is shown equipped with a photovoltaicelement 4650 to form a photovoltaic roofing element. The photovoltaicelement includes a junction box 4640. The junction box can be used tocontain interconnections of various photovoltaic cells of thephotovoltaic element, and to provide a single output for the electricalpower of the photovoltaic element. Wiring can emerge from or plug intothe junction box, and run from there through the wiring containmentstructure. As shown in FIG. 46, the wiring runs through the wiringcontainment structure, and is terminated with a connector 4632.

In certain embodiments, the wiring is run adjacent to a physical featurethat provides a physical interlock between adjacent photovoltaic roofingelements, such as the shiplap interlocking features described above or atongue-in-groove feature. In such embodiments, a wire containmentfeature can hold the wire in place such that it cannot inadvertently becaught or pinched in the physical interlock. For example, FIG. 47 showsa cross-sectional view of a corner of a frame structure 7200, in whichthe outer flange 4710 is designed to fit into a corresponding channel inan adjacent photovoltaic roofing element (shown in dotted line andmarked with reference number 4712). The wiring containment structure4720 (here, a channel) is formed in the downward-facing surface of theframe structure, adjacent the flange 4710 but acting to keep wiring 4730away from flange 4710. Fastener 4722 holds the wiring in place. In thisembodiment, the channel is formed between a downward-protruding wall4732 and the rest of the frame structure 4710. The channel can becontinuous, or can be formed as a series of discontinuous sections. Ofcourse, other shapes can be used for the wiring containment structure;in one embodiment, the structure is tube shaped (e.g., as one or moresections of conduit). While the wiring containment structure in theembodiment of FIG. 47 is shown as running vertically along the framestructure (i.e., in a top end-to-bottom end fashion), the person ofskill in the art will appreciate that the wiring containment structurecan run horizontally, diagonally, or in a combination of directions,depending on the particular wiring scheme envisioned.

In the embodiments described above, the wiring containment structuresare formed on the downward-facing surface of the frame structure, suchthat the wiring can be run underneath the photovoltaic roofing element.In other embodiments, the wiring is desired to be run along the topsurface of the photovoltaic roofing element, for example, in the headlaparea, such that it is covered by an overlying photovoltaic element. Insuch embodiments, a wiring containment structure can be formed on theupward-facing surface of the frame structure. For example, as shown inpartial cross-sectional view in FIG. 48, the wiring containmentstructure 4820 can be formed as an indentation in the frame structure4800, such that the wiring runs at or below the plane of theupward-facing surface of the frame structure, and does not protrude suchthat it interferes with the placement of an overlying photovoltaicroofing element 4805 (shown in phantom). In other embodiments, as shownin FIG. 49, the wiring containment structure 4920 is provided as araised feature disposed at the upward-facing surface of frame structure4900, and cooperates with a wiring containment structure 4925 formed onthe downward-facing surface of the overlying photovoltaic roofingelement 4905 (shown in phantom). In other embodiments, the wiringcontainment structure is disposed adjacent an edge of the framestructure.

The wiring containment structures as described herein can perform anumber of wiring routing functions. For example, as described above, thewiring containment structures can route wiring from the photovoltaicelement to the periphery of the photovoltaic roofing element forconnection to an adjacent photovoltaic roofing element and/or to alarger electrical system. In other embodiments, the wiring containmentstructure can allow for other wiring to be run along the photovoltaicroofing element. For example, photovoltaic roofing systems often include“home run” wiring that delivers collected power to a larger electricalsystem. Wiring containment structures can allow home run wiring to berouted from course to course, as shown in partial schematic plan view inFIG. 50. Wiring containment structures 5030 are formed on thedownward-facing surfaces of the frame structures 5005; wiring 5040 runsdown the roof in the wiring containment structures 5030. The wiring canbe provided within a conduit, such that the conduit fits within thewiring containment structures.

A wide variety of wiring containment structures can be used inpracticing various aspects of the present invention. Wiring containmentstructures can take a variety of shapes. For example, the wiringcontainment structure can be a series of holes or notches formed indownward-facing support structures, as described above. In otherembodiments, the wiring containment structure is formed as a channel. Inother embodiments, the wiring containment structure is a conduit. Agiven wiring containment structure can be formed as a unitary structure;or alternatively in spaced-apart sections (e.g., spaced-apart sectionsof conduit, or spaced-apart sections of channel). The wiring containmentstructure can include one or more fasteners, clips, or spots of adhesiveto hold the wiring against a surface and away from the downward ends ofany downward-facing support structures. In certain embodiments, thewiring containment structure includes a positive interlock that holdsthe wiring in the wiring containment structure (e.g., edges of a channelthat are slightly narrower, so that the wiring can “snap” in). Thewiring containment structure can be formed or molded as part of theframe, or can be added after formation of the frame, for example, viaadhesive, clip, weld, cleat, rivet, or other mechanical fastener. Whenholes or other features requiring wiring feed-through are used, thewiring may need to be fed through before any connectors are attached.When the wiring containment structure has an opening (e.g., a channel ora clip), it can be configured to face the roof deck (e.g., to be flushagainst the roof deck) when installed, thereby holding the wiring inplace.

A variety of suitable designs for wiring containment structures areshown in FIGS. 51A-51J.

When a wiring containment structure is a channel formed in anupward-facing surface of a frame structure, it can provide moisturehandling as well. Preferably, any wiring or other electrical componentsdisposed in a channel configured for moisture handling is otherwisewater-resistant. One embodiment of such a channel is shown in schematiccross-sectional and top views in FIG. 52. Channel 5220 is formed in theupward-facing surface of frame structure 5200. The channel structureincludes cut-outs that can collect water and admit it into the channel.Such cut-outs can be beveled, with a tapered edge.

In certain embodiments, the wiring containment structure is a separatecomponent, assembled onto the frame structure (for example, duringmanufacturing or during installation). A schematic cross-sectional viewof such a wiring containment structure is shone in FIG. 53. In thisembodiment, the wiring containment structure is a separate piece,disposed along the edge of a frame structure.

In certain embodiments, the frame structure includes a pocket, formed asa relatively large recess at the upward- or downward-facing surface ofthe frame structure. The pocket can extend from the surface, defined byfeatures extending therefrom; and/or can be formed as an indentation inthe surface. The pocket can be sized to provide a place for theinterconnection and protection of connectors. For example, as shown inpartial schematic plan view in FIG. 54, wiring 5440 can run throughwiring containment structure 5420 from a junction box 5450 to a pocket5425, where interconnections to adjacent photovoltaic roofing elementscan be made. In certain embodiments, the pockets are formed on thedownward-facing surface of the frame structure, to allow theinterconnection to be protected from the elements. The pockets can besized to fit the mated connectors and some slack wiring to allow forease of interconnection. Accordingly, in certain embodiments, matedconnectors and/or slack wiring are disposed in the pocket, as shown inFIG. 54.

Another aspect of the invention is a roof comprising a roof deck and aphotovoltaic roofing system as described herein disposed on the roofdeck. The photovoltaic roofing systems described herein can be utilizedwith many different building structures, including residential,commercial and industrial building structures.

There can be one or more layers of material (e.g. underlayment), betweenthe roof deck and the photovoltaic modules. The roof can also includeone or more standard roofing elements, for example to provide weatherprotection at the edges of the roof, or in areas not suitable forphotovoltaic power generation. In some embodiments,non-photovoltaically-active roofing elements are complementary inappearance or visual aesthetic to the photovoltaic roofing elements.Standard roofing elements can be interleaved at the edges of thephotovoltaic arrays described herein. In certain embodiments, thephotovoltaic roofing elements are simply disposed on top of analready-installed array of standard roofing elements (e.g., analready-shingled roof).

Another aspect of the invention is a kit for the installation of aphotovoltaic roofing system, the kit comprising a plurality ofphotovoltaic roofing elements as described herein, a plurality of sideflashing elements as described herein, adapted to interlock with thephotovoltaic roofing elements of the kit. The kit can further include aplurality of top flashing elements as described herein. The kit can alsoinclude a plurality of cant strip elements as described herein.

Another aspect of the invention is a method for installing aphotovoltaic array comprising disposing on a surface (e.g., a roof) andelectrically interconnecting a plurality of photovoltaic modules asdescribed herein. The disposal on the surface and electricalinterconnections can be performed in any desirable order. The method canfurther include disposing a cover over substantially laterally alignedelectrical elements of the photovoltaic array. In other embodiments, themethod can comprise placement of wiring within wiring containmentstructures as described herein.

Further, the foregoing description of embodiments of the presentinvention has been presented for the purposes of illustration anddescription. It is not intended to be exhaustive or to limit theinvention to the precise forms disclosed. As the person of skill in theart will recognize, many modifications and variations are possible inlight of the above teaching. It will be apparent to those skilled in theart that various modifications and variations can be made to the presentinvention without departing from the scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theclaims and their equivalents.

The invention claimed is:
 1. A photovoltaic roofing system disposed on aroof deck having a top end and a bottom end, the photovoltaic roofingsystem comprising: a plurality of photovoltaic roofing elements eachcomprising a frame structure having an upward-facing surface and adownward-facing surface having a top end and a bottom end, the framestructure having a headlap zone and an exposure zone, with the exposurezone disposed toward the bottom end of the frame structure, and theheadlap zone disposed toward the top end of the frame structure; and oneor more photovoltaic elements held in the exposure zone of the framestructure, the photovoltaic roofing elements being contiguously disposedon the roof deck to provide contiguously-disposed photovoltaic elements,the contiguously-disposed photovoltaic elements together having a topedge facing the top end of the roof deck, a bottom edge facing thebottom end of the roof deck, and two side edges, wherein in eachphotovoltaic roofing element the frame structure includes sidelapportions disposed at lateral edges of the frame structure, the sidelapportions having geometries interlocking with sidelap portions ofadjacent photovoltaic roofing elements to provide water drainagechannels; a plurality of roofing elements disposed adjacent and alongthe side edges of the contiguously-disposed photovoltaic roofingelements, along their side edges; and side flashing elements disposedalong the side edges of the contiguously-disposed photovoltaic roofingelements, each of the side flashing elements having a cross-sectionalshape comprising a vertically-extending feature disposed adjacent one ofthe side edges of the contiguously-disposed photovoltaic elements and aflange extending away from a lateral side at a downward end of thevertically-extending feature, with the flange facing away from thecontiguously-disposed photovoltaic roofing elements and being at leastpartially disposed between at least one of the plurality of roofingelements and the roof deck, wherein in each photovoltaic roofingelement, the sidelap portion at one lateral edge includes anupward-facing channel; and the sidelap portion at the other lateral edgeincludes a downward-facing flange disposed in the upward-facing channelof an adjacent photovoltaic roofing element; in each photovoltaicroofing element, the frame structure is rigid; the contiguously-disposedphotovoltaic roofing elements together are in a rectangular arrangement;and the photovoltaic roofing elements of the contiguously-disposedphotovoltaic roofing elements are disposed in a plurality of overlappingrows, with the headlap zones of the photovoltaic roofing elements of anoverlapped row being covered by the exposure zones of an overlappingrow; the photovoltaic roofing system further comprising one or more topflashing elements disposed along the top edge of thecontiguously-disposed photovoltaic roofing elements, the one or more topflashing elements having a bottom end disposed over the top edge of thecontiguously-disposed photovoltaic roofing elements, and a top enddisposed under one or more of the plurality of roofing elements disposedalong the top edge of the contiguously-disposed photovoltaic roofingelements; and a cant strip disposed under the bottom edge of thecontiguously-disposed photovoltaic elements and on top of an underlyingcourse of roofing elements of the plurality of roofing elements.
 2. Thephotovoltaic roofing system according to claim 1, wherein in eachphotovoltaic roofing element, the headlap zone is an attachment zone inwhich the photovoltaic roofing element is attached to the roof deck. 3.The photovoltaic roofing system according to claim 1, wherein in eachphotovoltaic roofing element, the frame structure is unitary and theheadlap zone of the frame structure has at the top end thereof a firstraised lip extending upward with respect to the upward-facing surface ofthe frame structure in the headlap zone.
 4. The photovoltaic roofingsystem according to claim 1, wherein in each photovoltaic roofingelement, at least one lateral side edge of the headlap zone does notinclude a ridge, such that water in the headlap zone can flow off of aside thereof.
 5. The photovoltaic roofing system according to claim 1,wherein the one or more photovoltaic elements are sealed to the framewith a sealant.
 6. The photovoltaic roofing system according to claim 1,wherein in each side flashing element, the flange extends at least 2inches under the at least one of the plurality of roofing elements. 7.The photovoltaic roofing system according to claim 1, wherein thephotovoltaic roofing elements are electrically interconnected.
 8. Thephotovoltaic roofing system according to claim 1, wherein the roofingelements are roofing shingles.